It must be a new promotion by Ruger. My LGS in northern AL has come out with several new Ruger rentals with mounted Lasers. The guns include:
MKIII in .22, SR9C in 9mm, 1911 in .45, GP-100 4" in .357 and SP101 2" in .357.

I have been curious about the lasers and this is a great way to learn about using them. I will start with the SR9C which is physically the same as my SR40C. The .22 might seem good for a starter but I have not fired one in many years. I have learned one thing in watching other people try these guns. It can be very embarassing! You look only at the green or red dot appearing on the target when you point the gun in the general direction of the target. Then you move the dot to the point of aim and fire. The problem is the dot wanders all over the target. It shows very clearly the motion of the gun as you pull the trigger. It can make every body laugh while a grown man cries in frustration. Consider wearing a mask or being the first in or last out!

In preparation for this, I tried dry-firing a GP-100 4" (no laser). I had given up on DA revolvers when I had a DA .22 revolver. I couldn't hit much with it and always used it in SA mode. The GP100 seemed to have an easy and smooth trigger pull in DA mode. I look forward to trying all these.

These lasers all seem to mount from the rail on semi-autos. I might buy one for my S&W M&P 40 or my Ruger SR40C and move it between the two for practice. I don't think it would be good on a carry gun. The Crimson Trace lasers that mount in the handle would be best for that.